Harry ii



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. third, grinding the hard mass 7-1.. s; tlhltl i C1 i it lta m XR 5999792 5R NiTli-i) STATES PROCESS or" T SPECIFICATION forming part of, Letters 3 Application filed March 6,1897. Serial No. 626,020. (No specimens.)

To all whom it may concern.-

Be it known that I, HARRY II. PIERCE, a citizen of the United States, residing at Toledo, Lucas county, Ohio, have invented a certain new and useful Process for the Treatment of Lime and the Product of such Process, of which the following is a specification.

The familiar objections and diiiicultics encountered in the storage, transportation, and use of common quieklime are its tendency to slake, heat, swell, and shrink, these changes frequently occurring after the lime is mixed and used with plaster and mortar, causing walls and ceilings to crack and chip elf. Another well-known dilliculty met with in the use of lime mortars and plasters is the length of time required for thesame to become hard throughout the mass when in place. lleretofore all lime mortars have required the action of air and the absorption therefrom of carbonic-aeid gas to render the work soiliciently hard. This process is an extremely slow and tedious one, the lapse of many years being sometimes necessary to cause this atmospheric action to form a carbonate of the whole mass and thus bring about the desired hardness of the mortar, except at or near the My invention relates to and its object is to provide means for overcoming the objections and di'lliculties here pointed out, and more particularly to provide a process by which the lime in its preparation for use is artificially highly carbonized, thus causing mortars and plasters in which such lime is used to harden more rapidly and uniformly than heretofore.

In United States Letters Patent granted to 'me July 23, 1805, No. 513,452, I. pointed out the advantages and claimed the process of treating limo which consists in, iirst, slaking quicklime to a putty; second, roasting said putty at a sufficient temperature to drive oil all adhering or uncoinbined moisture, and, thus obtained to a powder. The process there described was found to serve admirably to prevent the slaking, heating, and swelling of lime when stored or in transit or when mixed with niortars and plasters. 'lh'e slow and uniform hardening of the plasttr and mortar above search Room PATENT Fries.

REATENG LIME.

Patent No. 599,792, dated March 1, 1898.

referred to were, however, found still to exs ist, and the present process is devised as an improvement upon the process patented as above stated.

In practicing inyinvention common quicklime is first slaked to a putty, which may then be screened to remove foreign substances and bits of hard or unslaked lime. This putty is now fed into one end of a revolving iron cylinder and is caused to travel slowly to the opposite end of the cylinder, where it is discharged and conveyed to the grinding and boltinginachinery. Beneath the revolving cylinder is a fire of coke or the like, the combustion of which evolves carbon monoxid and carbon'dioxid. These gases on their way to the smoke-stack pass through the cylinder in whichthe hydrated lime is being constantly tumbled and thoroughly agitated. The hot gases on their way through the cylinder absorb and carry oil the excess of moisture, while the lime absorbs a large per cent. of carbon dioxid from said gases and is discharged from the cylinder thoroughly dried or roasted and highly carbonated. The degrce of heat and the time of exposure will vary according to the condition of the putty and the amountof moisture present; but the heat and time of exposure should be sullicient to drive oil the adhering oruncombined 8c moisture. I Care should be taken, however, not to subject the lime under treatment to a red heat or to such heat as will recalcinc the lime, as such temperature will rcconvert the mass to a quicklime. When the putty has been agitated and roasted in the presence of carbonic-acid gas, as above dc cribed, it becomes hard and white and oi." uniform strucure, and should now as the last step of my process be ground or otherwise pulverized to 9c the desired iinencss. The lime is now ready for use.

The substance thus produced may be kept indefinitely without air-slaking, will not slakc, heat, or change, retains its ttiiig qualities, is always-ready for use, and may be applied to any of the purposes for which lime is cdmmonly used, and espeeiall y in plasters and mortars. lllortar in which this lime is used becomes uniformly hard in a short time,

thus avoiding the tedious Waiting for nature derthe product thus obtained, substantially byatmosplleric action to furnish the carbonic as and for the purpose specified. acid necessary to form the hard carbonates 2. As an article of nimiulztcture,lime which found in old mortars. as quicklin'ie has been slulicd toaputty, then 15 5 W'hat I claim, and desire to secure by 'Letroasted in the presence of carbonic-acid gas, ters Patent, isand then pulverized, substantially as and for 1. Theherein-described process of treating the purpose specified. lime which consists in, first, slziking p1ick- HARRY ll. PIERCE. lime to a putty; second, roasting the hydrate In presence 0l :0 of lime thus formed in the presence of cer- L. E. BROWN,

bonic-acid gas, and third, grinding tozt pow F. M. DOTSON. 

